This invention relates to an electromagnetic shielding gasket which is attached to a rim, an edge or other portion of a board member and creates an electrical contact with a desired contact portion, thus establishing an electromagnetic shielding effect.
Such an electromagnetic shielding gasket is proposed in the Japanese Laid-open Patent Application No. 2-246199 which discloses a shield structure for a high-frequency module. As shown in FIG. 10 of the drawings, a metallic case 103 is separated by a partition plate 101 into regions in which high-frequency circuits are mounted. A shield plate 107, described later, is attached to the partition plate 101 such that the partition plate 101 is in electrical contact with a lid 105 when it is in a closed position, thus obtaining an electromagnetic shielding effect.
The shield plate 107 is composed of an elongate main plate member 111 and two opposed side flaps 109 formed by folding both side portions of the shield plate 107 almost normal to the main plate member 111. When the shield plate 107 is attached to the partition plate 101, the side walls of the partition plate 101 are held between the side flaps 109. The shield plate 107 is provided with parallel resilient fins 113 formed by partially cutting the main plate member 111 in U shapes and raising the cut portions. Free ends of the resilient fins 113 contact the underside of the lid 105 when it is closed, thus providing an electromagnetic shielding effect.
As shown in FIG. 10, however, the resilient fins 113 can only contact the underside of the closed lid 105 which is almost normal to the partition plate 101. The resilient fins 113 fail to contact any surfaces which extend parallel to the side walls of the partition plate 101.
Furthermore, the resilient fins 113 are formed integrally with the main plate member 111, thus weakening the main plate member 111. When the shield plate 107 is attached to a narrower partition plate, the main plate member 111 and the integrally formed resilient fins 113 must also be narrow, thus decreasing the structural rigidity of the shield plate 107. Accordingly, the length of the resilient fins 113 is also limited.